Abstract

Hydrological Mediterranean situation has undergone rapid changes over the last years. This fact causes heavy consequences for both regional water authorities and water utilities to properly plan the future groundwater management. This work analyzes the presence of hydrological changes at local scales, through the reconstruction and time series analysis of hydroclimatic variables (precipitation and temperature) in a coastal Tuscany watershed. For this purpose, the following statistical analyses were performed: (a) change point analysis; (b) Mann–Kendall and Sen’s slope tests; (c) precipitation concentration index calculation; (d) analysis of anomalous data; (e) Autoregressive Integrated Moving Average model (ARIMA). The climate variation impact on the water cycle for the study area was then assessed. Although a significant temperature trend was not defined, it is possible to observe a growing trend starting from 1990, as confirmed by larger scale studies. The results of the Mann–Kendall test (p value = 7.3425e−06) and of the Sen’s slope test (− 6.6) for annual precipitation show a statistically significant tendency to decrease, enough to cause a shift in rainfall regimes. The average monthly precipitation values fitted by the ARIMA model show a decrease in time with a maximum expected monthly precipitation of 170 mm (95% confidence level). This scenario reflects rainfall change pattern observed in the study area, where rainfall regime starts in 1990 from sub-humid climate system (annual precipitation between 600 and 1200 mm) to reach a semi-arid one today, with the annual precipitation ranging, at the present day, between 400 and 600 mm (about − 40% respect the previous 30 years).

Graphic abstract

中文翻译：

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水文变化：它们是否存在于地方尺度？

摘要

在过去的几年中，地中海的水文状况发生了迅速的变化。这一事实给地区水务主管部门和水务部门造成了严重后果，无法正确规划未来的地下水管理。这项工作通过对托斯卡纳沿海流域的水文气候变量（降水和温度）进行重建和时间序列分析，分析了当地尺度上水文变化的存在。为此目的，进行了以下统计分析：（a）变更点分析；（b）曼恩·肯德尔和森的边坡测试；（c）降水浓度指数的计算；（d）分析异常数据；（e）自回归综合移动平均模型（ARIMA）。然后评估了气候变化对研究区域水循环的影响。尽管没有定义明显的温度趋势，但有可能从1990年开始观察到增长趋势，这一点已得到更大规模研究的证实。曼恩·肯德尔（Mann–Kendall）检验的结果（p值= 7.3425e−06）和针对年降水量的森氏斜率测试（− 6.6）显示出统计学上显着的下降趋势，足以引起降雨体制的变化。ARIMA模型拟合的平均月降水量显示时间减少，最大预期月降水量为170毫米（置信度为95％）。这种情况反映了研究区域观测到的降雨变化模式，该地区的降雨始于1990年，从半湿润的气候系统（年降水量在600至1200毫米之间）发展到今天的半干旱气候，年降水量范围为今天，介于400到600毫米之间（相对于前30年，约为-40％）。

图形摘要